/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.confignode.manager.node.heartbeat;

import org.apache.iotdb.commons.cluster.NodeStatus;
import org.apache.iotdb.mpp.rpc.thrift.TLoadSample;

/**
 * DataNodeHeartbeatCache caches and maintains all the heartbeat data
 */
public class DataNodeHeartbeatCache extends BaseNodeCache {

    private volatile TLoadSample latestLoadSample;

    /**
     * Constructor for create DataNodeHeartbeatCache with default NodeStatistics
     */
    public DataNodeHeartbeatCache() {
        super();
        this.latestLoadSample = new TLoadSample((short) 0, 0, 0, 0);
    }

    @Override
    protected void updateCurrentStatistics() {
        NodeHeartbeatSample lastSample = null;
        synchronized (slidingWindow) {
            if (slidingWindow.size() > 0) {
                lastSample = slidingWindow.getLast();
            }
        }
        long lastSendTime = lastSample == null ? 0 : lastSample.getSendTimestamp();

        /* Update load sample */
        if (lastSample != null && lastSample.isSetLoadSample()) {
            latestLoadSample = lastSample.getLoadSample();
        }

        /* Update Node status */
        NodeStatus status = null;
        String statusReason = null;
        // TODO: Optimize judge logic
        if (System.currentTimeMillis() - lastSendTime > HEARTBEAT_TIMEOUT_TIME) {
            status = NodeStatus.Unknown;
        } else if (lastSample != null) {
            status = lastSample.getStatus();
            statusReason = lastSample.getStatusReason();
        }

        /* Update loadScore */
        // Only consider Running DataNode as available currently
        // TODO: Construct load score module
        long loadScore = NodeStatus.isNormalStatus(status) ? 0 : Long.MAX_VALUE;

        NodeStatistics newStatistics = new NodeStatistics(loadScore, status, statusReason);
        if (!currentStatistics.equals(newStatistics)) {
            // Update the current NodeStatistics if necessary
            currentStatistics = newStatistics;
        }
    }

    public long getFreeDiskSpace() {
        return latestLoadSample.getFreeDiskSpace();
    }
}
